Born in Cwmbran, Wales, Gabbidon played youth football for local sides Court Farm and Cwmbrân Town.

[3] Gabbidon began his senior career at West Bromwich Albion, joining as an apprentice in November 1996 before turning professional in July 1998.

[4] He made his Albion début in a 1–0 home defeat against Ipswich Town on 20 March 1999 and, utilised as a right-back, he went on to make 27 appearances for West Brom in all competitions.

[6] Gabbidon signed a permanent four-year deal with Cardiff City in September 2000, for a fee of up to £500,000 depending on appearances and future honours.

[7] His performances in the 2001–02 season helped Cardiff to the Division 2 play-offs, saw him make his senior international debut for Wales in March 2002[8] and win the Welsh clubman of the year award in October 2002.

[10] A back injury that had troubled him for some years, forced him off the pitch during a match against Barnsley in November 2002[11] and it was not until April 2003 that he returned to competitive action in a reserve game.

[13] He missed several games at the beginning of the 2003–04 season with a heel injury[14] but his assured performances at centre-half, and those of striker Robert Earnshaw, led club chairman, Sam Hammam, to insist in December 2003 that "Our top young players are going nowhere" in the January 2004 transfer window.

[21] A financial crisis at Cardiff at the end of the season led to Gabbidon being unsure of his future at the club and he was sold to West Ham United in July 2005 to help cut the wage bill.

[24] He established himself in central defence alongside Anton Ferdinand and helped West Ham to a mid-table position in the Premier League in the 2005–06 season and to the FA Cup final in May 2006, receiving a runners-up medal.

"[29] Injuries meant Gabbidon played no football for West Ham from December 2007 until August 2009 when he made his return in the League Cup game against Millwall.

[32] On 17 January 2012, Gabbidon scored his first first-team goal since March 2005, a header from a corner in QPR's 1–0 FA Cup third round replay tie win against Milton Keynes Dons.

[43] In August 2015, Gabbidon joined his hometown club, Welsh Football League Division Three side Panteg, where his brother David also played.

[47] He was an unused substitute in that match and was again called into the senior squad for a friendly game against Argentina in February 2002[48] but it was not until the next month that he made his debut in a 0–0 home draw against the Czech Republic on 27 March 2002.

Wales & Celtic midfielder Joe Ledley who is also a close friend of Gabbidon, has also called for the West Ham man to return to the international fold.